Vehicle drive mechanism



Sept. 10, 1940. F. L. FREEMAN VEHICLE DRIVE MECHANISM 1938 5 Sheets-Sheet 1 Original Filed Jan. 2;

INVENTOR fiI'TORNEYS.

sept- 1940. F. FREEMAN 2,213,981

VEHI CLE DRIVE MECHANI SM Original Filed Jan. 21, 1938 5 Sheets-Sheet 2 INVENTOR "I Ewan/r L. Freeman BY E ATTORNEYS Sept. 10, 1940. F. FREEMAN VEHICLE DRIVE MECHANISM Original Filed Jan. 21, 1938 5 Sheets-Sheet 3 INVENTOR 521224 L. fies man BY fiTTORNEYS Sept. 10, 1940. F FREEMAN 2,213,981

I VEHICLE DRIVE MECHANISM Original Filed Jan. 21, 1938 5 Sheets-Sheet 4 W I BY p 0, 1940. F.- 1.. FREEMAN 2,213,981

VEHICLE DRIVE MECHANISM Original Filed Jan. 21., 1938 5 Sheets-Sheet 5 Patented Sept. 10, 1940 UNITED STTES PATENT OFFICE VEHIGLE DREVE MECHANISM Frank L. Freeman, Detroit, Mich.

Claims.

This invention relates to vehicle drive mechanisms, and the present application is divisional to my application, Ser. No. 186,129, filed January 21, 1938.

5 An object of the invention is to provide a drive mechanism for front and rear pairs of wheels mounting the rear portion of a vehicle frame, and to transmit the drive to such wheels through an arrangement of gears adapted to more powerfully increase the transmitted torque than prior constructions.

Another object is to establish a connection for transmitting forwardly or rearwardly acting thrust from one to the other of two normally parallel axles, and to adapt such connection to adjust itself to and function in non-parallel positions which said axles may assume for steering purposes.

A further object is to transmit a drive to a pair 2 of aligned vehicle wheels through a set of differential gears and to interpose a change-speed between the differential gears and each of said wheels.

A further object is to adapt the two changespeed gearings aforesaid to be correspondingly shifted by a single control mechanism.

A further object is to provide a unitary housing accommodating a. pair of aligned axial sections, a gearing for differentially driving such secadtions, a pair of change-speed gearings through which the differential drive is transmitted to the axial sections, and a change-speed gearing through which a drive is transmitted to the differential gearing.

These and various other objectsare attained by the construction hereinafter described and illustrated in the accompanying drawings, wherem:

Fig. 1 is a somewhat diagrammatic top plan view of the chassis of the improved vehicle, showing the positions and paths of the various wheels, in exercising a steering control.

Fig. 2 is an elevational view, partially in section on the line 2-2 of Fig. 3, showing particularly one of the bars bridged between the two driven axles to mount a leaf spring and transmit load from the same to said axles.

Fig. 3 is a cross sectional View of the chassis,

f taken on the line 3-3 of Fig. 4, and showing particularly the provision for mounting the frame on and transmitting its load to said bars.

Fig. 4 is a top plan view of the chassis, partially in section on the line lt of Fig. 3, and

illustrating the various load-transmitting and driving connections between the two driven axles. Fig. 5 is a cross-sectional view, taken on the line 5-5 of Fig. 4, and particularly showing two change-speed gearings, and an interposed drum for housing a differential gearing driving both sets of change-speed gears. 5

Fig. 6 is a vertical, elevational, sectional detail of the parts forming a swivel or fifth wheel connection between the frame and its running gear, taken on the line 6--6 of Fig. 3.

Fig. 7 is an elevational view, partly in section 10 on the line l'l of Fig. 4, showing particularly the relation of the two axle housings and a change-speed gearing carried by one thereof and adapted to vary the drive to both pairs of driven wheels. 5

Fig. 8 is a horizontal sectional detail, taken on 1 the line 8-,-8 of Fig. 7 and showing features of the connection between the rear axle housing and one of the axle-bridging bars.

Fig. 9 is a crosssectional view, taken on the 20 line 9 9 of Fig. 7, showing one of said bridging bars in its relation to the rear axle, and also showing a latch member on said bar.

Fig. 10 is a horizontal sectional detail taken on the line l0-|B of Fig. '7, showing the mount- 5 ing for the forward end of one of the axle-bridg ing bars.

In these views, the reference character I designates a motor vehicle frame carried at its front 7 end by an axle 2, the wheels 3 of Which are 30 swiveled, as is common, for steering purposes (see Fig. 1). The rear portion of the frame is mounted on front and rear pairs of wheels 4 and 5, each having a driving axle section 5 (see Fig. 1 5). The outer portions of the sections 6 occupy 35 tubular housings l, rigidly carried by and projecting oppositely laterally from front and rear gear housings, generally designated 8 and 9.

A single pair of leaf springs iii transmit load from the frame to the four driven wheels and are m mounted to afford the rear driven wheels, together with their axle sections 6, housings l and the gear housing 9, a limited angular play relatively to the frame for steering purposes. Thus saidsprings, which are upwardly bowed between 45 their ends, seat freely on a pair of parallel bars li, upwardly channeled to hold the springs in place. The end portions of said bars are cylindrical and preferably tubular and lie beneath the housings 1. Each of said end portions is carried 50 by an annular ball member l2 universally rotative in a spherical socket member !3 clamped by means of a bracket [4 on the overlying housing 1. To facilitate engagement of the brackets It with the housings l and to further facilitate assembly of the ball and socket members, each bracket is formed in two parts, each carrying half of the corresponding socket member, said parts being rigidly interconnected by bolts l5 and firmly clamped thereby on the corresponding housing l. The forward ends of the bars H are pinned as indicated at it to the corresponding ball members if, while the ball members 52 mounting the rear ends of said bars are free to slide on the cylindrical rear portions of said bars to afford the rear driven wheels and their axle assembly angular travel. Rearward angular movement of either end of the rear axle assembly is limited by stops ii at the rear ends of the bars ll, such stops being preferably carried by plugs l8 screwthreaded into said ends. Forward angular movement of said assembly is limited by suitable stops l9 carried by the bars ll, hereinafter more fully described.

For transmitting load from the frame to the springs, a pair of brackets 25 are bolted or otherwise attached to the sills of the frame, and seat through saddle members 21 upon blocks 22, superposed on the mid portions of the springs, each block having a pair of depending plates 23, be-

tween which the leaves of the corresponding spring are snugly engaged.

To swivel the frame so that it may turn for steering purposes on the support established by the springs ill, the blocks 22 are connected by an arched yoke 2%, having its top portion disposed between the sides of the frame, and having rectangular portions 25 beneath said sides, which portions carry cylindrical trunnions 2G fitted in correspondingly shaped openings in the blocks 22 and retained therein by the heads of bolts 2? tapped into the end faces of said trunnions. Above said yoke, a rigid connection is established between the sills of the frame by a heavy cross bar 28, which centrally rigidly carried a king bolt 29 rotatable in the yoke 24, (see Fig. 3) and preferably headed beneath the latter to maintain the same in a desired proximity to the cross bar. Also it is preferred to form the yoke and cross bar with circular enlargements 2 3a and 28a, centered at the bolt 2%, assuring a swivel bearing of ample diameter, and anti-friction means may be interposed between said enlargements, such as the set of balls 38 illustrated (see Figs. 3 and 4). It is preferred to further interconnect said yoke to the frame by forming each bracket Jill with a pair of depending extensions 3i beneath the frame, the corresponding portion 25 of the yoke being positioned between such extensions and a plate 32 rigidly connecting such extensions being engaged beneath such portion 25. The brackets Ell thus form connections, additional to the bolt'25, between the frame and yoke 24, the paired extensions 3i being, however,

l spaced apart adequately to afford the frame its desired swivel movement about the bolt 29, as best appears in Fig. 4. Fig. 4 also discloses how the brackets 26 are adapted to swing with the frame, for steering purposes, about the axis established by the bolt 29, by forming certain faces speed gear chambers 3d and a differential gearing chamber 35 between the chambers 34, and the illustration of the housing 8 in Fig. 5, showing said chambers and the gears therein, is for I practical purposes, illustrative also of the gear upwardly spaced from the axle sections 6, and

each such shaft may drive the underlying axle section through either of two meshed pairs of gears 3 and $5 occupying the corresponding chamber 3Q. Said gears are, of course, adapted to establish different drive ratios, selective by the shifting of clutch collars lli, one of which is splined on each shaft 3? between the two gears on such shaft. Preferably the collars ltl on the aligned shafts are controlled in common by mounting shifter yokes ll for said collars on aligned slide rods d2, projecting into the chamber 35 and connected within the latter by links 43 to a suitable control rod M, slidable longitudinally of the vehicle. Preferably a connection 45 between the rods M, carried by the housings 8 and 9 adapts such rods for actuation in unison.

The drums 3i? which house the front and rear differential gearings carry the usual beveled ring gears 45, driven by pinions ll (see Figs. 5 and '7). Said pinions are fixed on shafts 18 and lfia, the axle housing 2-3 having a forward extension ts journaling the shaft 48a, and the shaft 43 being journaled in the upper portion of a changespeed gear casing 58, rearwardly projecting from the mid portion of the axle housing 8.

A shaft 52, operating in a torque tube tablishcs a drive connection between the shafts (i8 and 58a, suitable universal joints 53 being provided at the junctures of said tube with the extension 29 and casing 58, and said shafts being universally joined interiorly of the joints 53.

The casing 5d houses two pairs of gears 54, 56a and 55, providing alternative drives to the shaft 48 from an underlying shaft 53 journaled in and forwardly projecting from said casing. A clutch collar til, splincd on the shaft 48 between the gears 56 and 55, is adapted in a well-known manner to establish either thereof in driving engagement with said shaft. A shifter yoke 58, suitably pivoted within the casing 5&3, engages the collar E21 and is actuable by a lever 59, exteriorly mounted on said casing, to establish the collar in either of its driving positions or a neutral one. A rod iii] for actuating the lever 59 extends forwardly from the latter to any desired point of control.

A motor 55, carried in any suitable manner by the front portion of the frame l, transmits a drive to the shaft fall through a shaft 62, mounted in the usual torque tube 63, the usual concentric universal joints fi l being provided at each end of the torque tube and shaft therein and the usual change-speed (or transmission) gearing (not shown)-being housed, as indicated at 65, in rearward proximity to the engine to transmit selective speeds to the shaft 62.

To transmit thrust from the housing 9 to the housing 8, in forward travel of the vehicle and a reverse thrust in rearward travel, the two said housings are connected by a pair of heavy diagonal rods 68, occupying a freely crossed relation, whereby said rods jointly have substantially an X form, their crossing being arranged at a point substantially beneath the fifth wheel axis established by the king bolt 29. The joints 61 between said rods and the housings 8 and 9 ends.

afford a. relative universal pivotal play between the rods and housings, the ends of the rods engaging each housing being located by such joints equidistantly from a plane medial to the housing To permit said rods to normally occupy the same horizontal plane and also allow the described crossed relation, one of said rods comprises, at its mid portion, an open-sided boxshaped member 68, through which the other rod freely passes, the opening of the member 68 being adequate in size to afford the intended relative angular or vertical play of the rods without mutual interference.

A pair of radius rods 69, connected to the tubular end portions 1 of the axle housing 8, extend convergently forward and are welded or otherwise rigidly secured at their forward ends to the front end .portion of the torque tube 63.

In rearward travel of the described vehicle, it is not feasible to exercise a steering control of relative angular play between the leading and trailing rear wheels without undue complication, and it is preferred therefore to provide for looking said wheels against any such play, at least in a horizontal plane, preliminary to rearward travel of the vehicle. Thus, pivoted upon and straddling each bar I I, is a heavy latch member I I, adapted to be swung about its pivots I2 from a non-latching, upstanding position shown in full lines in Fig. 7, to the rearwardly projecting, latching position shown in dash lines in said figure, said member having an arch form, adapting it to engage the side as well as the top of the corresponding bar II, in said dash line position. In the latching position of the two members II, said members terminally engage the rear ball members I2, and thus form struts resisting any forward sliding of said members I2 on the bars II. Consequently in the latching position of the members II, the axle housing 9 and its wheels are restrained from any angular play relative to the frame or the axle housing 8. Any suitable provision may be made for an exercise of remote control over the latch members I2. Thus, as illustrated, each of said members is engaged by a forwardly extending control rod I3, springs I4 being mounted on said rod at opposite sides of the corresponding member I2 to resist any tendency to rattle. It is preferred to form the stops I9, hereinbefore mentioned, as a pair of arcuate lugs formed on each latch member I I at opposite sides of the corresponding bar II, said lugs being so spaced from the stops II, when the latch members are in their raised release positions, that the centers of ball members I2 are midway between said stops and lugs when the housing 9 is definitely transverse to the frame.

In the operation of the described invention, load is transmitted from the sills of the frame to the springs I8 through the brackets 20 and saddle members 2|, without imposing load stresses on the swivel seat afforded by the yoke 24 to the cross-bar 28. The leaf springs deliver such stresses to the bars II, whence they are trans:- ferred substantially equally to the two axle housings 8 and 9, and thence to the leading and trailing rear wheels of the vehicle.

Upon a change in the direction of travel of the vehicle, the frame I swivels about the king bolt 29, whereby the cross bar 28 assumes an acutely angular relation to the yoke 24 (see Fig. 1). This relative angular travel will be slight, and the spaced relation of the paired downward extensions 3| (best appearing in Figs. 2 and 4) is a sufficient provision for the entailed movement of the yoke extremities. The leading rear wheels 4 will adjust themselves to the arc of road travel prescribed by steering control of the front wheels, and the trailing rear wheels 5 Will also adjust themselves to such'aro, the axes of said wheels and the corresponding housings thus assuming the angular relation to the frame illustrated in Fig. 1. As said housings thus swing, the rear ball members l2 will slide freely on the cylindrical rear portions of the bars II, and both the front and rear ball members I2, will rotate, as required, in their socket members l3. Any extreme relative angularity between the housings 8 and 9 will be prevented by engagement of the ball members I3 with the stops I1 and I9. The universally pivotal connections of the rods 66 to the axle housings allows said rods to adjust them selves to the relative angularity of such housings, while still exercising their thrust-transmitting function. The universally pivotal connections established between the housings 8 and 9 and each of the bars II and 66 also serve to afford necessary relative vertical play of the front and rearv axle housings, or angular play in a vertical plane of one thereof. The drive shaft 5! and its torque tube 52 will accommodate themselves to relative angular travel of the housings 8 and 9, owing to employment of the universal joints 53.

Efiecting a speed reduction of the transmitted drive, between the differential gearings and the driven wheels, reduces the stresses imposed on said gearings and permits use of lesser dimensions for said gearings than would be feasible if the common and more obvious practice were followed of effecting all desired speed reductions at a point or points between the motor and differential gearings.

The gears 54, 54a, and 55, 55a provide for two selective variations of driving speed and the gears 38 and 39 afford two additional variations. Thus if within the usual change-speed gear casing 65, there is made the usual provision for three changes of speed in forward travel, the total number of differently geared forward drives available will be twelve, thus permitting the vehicle to be very closely adapted to different driving and load conditions. Furthermore, the provision of the several described successively acting speedreducing gearings will permit of a much greater application of tractive force when the aggregate reduction is a maximum, than has been heretofore afforded in vehicles serving a similar purpose, the available traction being further increased through application of a drive to both the leading and trailing rear wheels.

The weight added to that of the vehicle by the gears 38 and 39 and their casings tends materially to lower the center of gravity of the vehicle, as a whole, and consequently increases stability as compared to prior practice.

The construction provides for a substantially equal distribution of load to the two rear axles, while affording such free relative vertical play of said axles or relative angular play thereof in a vertical direction, as may be entailed by projections of depressions in any surface traversed by the vehicle.

The invention is presented as including all such modifications and changes as come within the scope of the following claims.

What I claim is:

1. In a vehicle, the combination with an elongated frame and two axle housings spaced 1ongitudinally of and supporting the frame, of a pair of aligned live axle sections journaled ineach of said housings, a pair of wheels driven by each pair of axle sections, a pair of aligned shafts mounted in each axle housing parallel to said axle sections, means in each axle housing for driving the respective axle sections from the respective shafts at selective speeds, a differential gearing in each axle housing for driving said aligned shafts in such housing, a common drive means for the differential gearings in both housings, including a speed-selective gearing carried by one of said housings, and a selective control for said gearing, independent of the first-mew tioned means for effecting speed selection, and a common means for effecting speed selection within both axle housings.

2. In a vehicle, the combination with an elongated frame, of a pair of axle housings spaced longitudinally of and carrying such frame, a pair of aligned live axle sections ujornaled in each housing, a pair of aligned shafts journaled in each housing approximately above said axle sections, drive connections from the respective shafts to the respective axle sections, a differential gearing associated with and driving each pair of aligned shafts, two shafts extending longitudinally of the vehicle and journaled one in each housing for driving the differential gearings, a shaft forming a drive connection from one to the other of said drive shafts for the differential gearings, a main drive shaft mounted on one of said housings substantially beneath and parallel with the differential gearing drive shaft journaled on such housing, and means establishing a drive at selective speeds from the main drive shaft to the overlying shaft.

3. In a vehicle drive mechanism, the combination with an elongated frame, and two axles supporting the frame and spaced lengthwise thereof, and relatively angularly movable in a substantially horizontal plane, each axle comprising two substantially aligned axle sections, drive gearing for said sections and a housing for such gearing, of a common means for driving the gearings of both axles, and a pair of freely crossed thrust rods universally connected at their ends directly tothe housings of the two axles, whereby said axles may freely conform themselves to angular movement of the frame incident to a steering control of the vehicle.

4. In a vehicle drive mechanism, the combination with spaced front and rear axle housings, of a pair of substantially aligned axle sections journaled in each housing, a differential gearing in each housing for driving the corresponding axle sections, a drive connection between the two differential gearings, universally mounted on said housings, and freely crossed thrust connections between the two housings, universally engaged with the housings and disposed beneath said drive connection, and affording the axles a relative angularity to freely conform to a steering control of the vehicle. 7

5. In a vehicle, the combination with two axle housings spaced longitudinally of the vehicle, a pair of aligned live axle sections journaled in each housing, a differential gearing in each axle housing, means for driving the differential gearings in common, corresponding chang -speed drive gearings in each housing affording selective drive to each axle section in said housing from the differential gearing in said housing, and a common means for selecting a like drive to the axle sections of both housings.

FRANK L. FREEMAN. 

